The present invention relates to computer animation. More specifically, the present invention relates to computer animation based upon motion captured data.
In computer animation, a user, known as an animator, typically specifies poses for models of an object on a computer system. Based upon the specified poses with respect to time, the object may appear to be animated in a series of rendered images. The inventors of the present invention have recognized that specifying poses of objects via object models is a very time consuming process. As an example, a face of an animated character may have about 100 individually adjustable parameters that determine positions for 20,000 surface points. Accordingly, animation of a character's face, for example, is a slow and painstaking process.
To facilitate posing models of objects in a computer animation environment, the assignee of the present patent application, ImageMovers Digital has pioneered the use of physical motion capture techniques using live actors. By way of example, ImageMovers has used a combination of motion capture techniques and traditional computer animation techniques to produce feature-length films including: “The Polar Express” (2004), “Monster House” (2006), “Beowulf” (2007), which have garnered several Academy Award nominations.
The inventors of the present invention have recognized that although motion captured data may assist an animator in the animation process, animators still need to refine such animation, by hand. One reason for this, is that motion capture data, especially of the face of an actor, typically only provides low-resolution, wire-frame-like data, that provides very coarse animation data. Another reason, is that when motion captured data alone is used to drive computer animation, the resulting computer animation often looks stiff and not esthetically pleasing. Still another reason is that animation using motion capture data is typically limited to the poses that are captured.
One problem recognized by the inventors of the present invention with animators modifying motion captured data includes, that it is very easy for an animator to pose “off-model.” In other words, it may be easy for an animator to stray from desired characteristic poses. As merely an example, suppose an actor was known for having a characteristic mannerism such as a wink or a smirk and that mannerism was motion-captured. In the animation process, the animator may start with the motion captured mannerism, but then may ruin such poses unintentionally when refining the animation. The resulting posed model would then be considered “off-model” because the object does not behave the way the actor did.
Accordingly what is desired are methods and apparatus for facilitating the use of motion captured data for computer animation, without the drawbacks described.